Stirrup mats are used in connection with reinforced concrete products in order to provide added shear stress reinforcement for the concrete. A stirrup mat typically comprises a mat formed of a wire grid having a series of reinforcement prongs (or loops) attached to the wires so as to extend at right angles to the plane of the mat. Stirrup mats usually are attached manually by wire ties to one of two concentric wire grid reinforcement cages used for the reinforced concrete. The mat may be attached to the inner or outer side of either of two spaced wire cages, with the prongs of the mat extending between the cages. Attachment of a stirrup mat to a reinforcement cage by means of wire ties is a time consuming process that often involves two people. One person is required to hold the mat in place against the cage, while another person manually ties the stirrup mat to the cage with wire ties. While a single person usually can tie a four foot stirrup mat to a cage, two people usually are necessary for a stirrup mat that is six to eight feet long.
In order to overcome the drawbacks with manually attachable stirrup mats, some self-locking stirrup mats have been developed, wherein the mats are clipped to the cages by clips integrally attached to the mats. Applicant's U.S. Pat. No. 5,924,458, which is incorporated by reference, discloses a self-locking stirrup mat including integral clips.
An object of the present invention is to provide an improved clip-on stirrup mat that can be attached to both single and double wrapped cages (wherein an inner or outer cage includes a double layer of wire grid reinforcement).